All the WiSpy gives you is power by frequency. You can't tell anything about what the device actually is. You could try and figure out which of your neighbors had a WiFi device on the same channel as you but that's about it. And really, unless the device is actually sending a lot of data you'll never even notice it in the noise. Thats my experience in using one.

It seems like a massive ooversight not to include a WiFi decoding module if you're going to build that big block of software for spectral analysis.

Quote:

So plainly physics says yes then?

No, not with regard to triangulation. When you use the moving method, you are in effect creating multiple individual read points. That is how you can (eventually) isolate the signal of choice down to a reasonably limited area.

You simply can't do that with a static omni. You can't even do it with two static omnis. It would require a minimum of three, to isolate a signal point in a 2D plane.

Strawman. I'm not going to use one, two or three static omni's. I'm going to go out with my laptop and take 100 samples, effectively giving me 100 static omni's providing data. I'm going to have so many omni's that I won't even need math to guess where the AP is. I can just plot the sample by X,Y and color by signal strength and my brain will be able to see where the AP is likely to be. You're making this whole thing harder than it really is because you're starting with the assumption that getting samples is expensive. And maybe sometimes it is, but not in this case.

Actually, he never said he wanted to triangulate using a static access point. That was just a strawman put up by other posters as to why what he was asking for was somehow difficult or even impossible. There are in fact lots of solutions which locate access points, and locating an active client is not really any different.

I am pretty sure that, 'This is similar to using cell towers to "triangulate" a cell phone. I want to locate the device connected to my private wifi,' was not brought up by anyone but ColonelMustard, aka molo's boss.

Quote:

Ummm, all the times I've gone out and taken surveys and the software nails the location of my access points tells me that no, it's not that hard.

Was he asking for locations of APs? Maybe you should go back and re-read the OP since you seem so unfamiliar with it, then come back and tell us what we did wrong.

Sigh...it's not a strawman. The OP mentioned triangulation! I'm simply explaing WHY it doesn't work. Since the OP specifically mentioned it, it's not a strawman of any type. He specifically called out cell phones...cell phone triangulation works because you almost always have 3 or more towers that are receiving a signal from an individual phone, and using strength of signal means you can locate it within a reasonable margin of error. (you also know exactly where each of these towers are...which is also a requirement for location)

Quote:

You're making this whole thing harder than it really is because you're starting with the assumption that getting samples is expensive. And maybe sometimes it is, but not in this case.

No, I'm not. A *directional* antenna means I don't have to wander around and take those 100 samples. I don't need to build a full heatmap just to isolate one thing. Going back to my code examples:

Code:

A | B

If I'm the omni in the middle, I'm screwed, and I need to keep moving around. If I have directionality, I can simple spin in place to eliminate a VAST majority of the potential locations...as I now know in which direction the signal of interest lies...but I still don't know how far away it is. I can get that by moving some distance to one side or the other, then retraining. The point at which my two directional lines intersect is where the device in question lies. Two measurements and I now know within reasonable certainty where this signal of interest is.

Strawman. I'm not going to use one, two or three static omni's. I'm going to go out with my laptop and take 100 samples, effectively giving me 100 static omni's providing data.

What in the OP's statements entitles you to the belief that you can move around? If you're going to call "stationary" as strawman, then I don't see how "motion" isn't a strawman too. Logically, that particular variable is entirely indeterminate.

Quote:

I'm going to have so many omni's that I won't even need math to guess where the AP is. I can just plot the sample by X,Y and color by signal strength and my brain will be able to see where the AP is likely to be.

Sure, because actual homes tend to be spaced pretty far apart, and one can get great geometry just moving between them.

So plainly physics says yes then?

You're trolling, right? If you can move, you're not stationary!

Go back and look at wrote I wrote originally: I noted if you could move around ("foxhunt") then it would be possible, but quite difficult. However, it doesn't change the fact that if you can't move around, then it will be either mathmatically impossible or practically infeasible (the math works, but the numbers are useless).

Yes, if the building is an apartment building, then the OP might be able to walk up and down the hallways and get a fairly reasonable answer. The answer might even be definitive if only a few people use WiFi. It might be useless too. But there's plenty of buildings where doing that may not be feasible. If you're one office of many in a crowded corporate building, then running around the halls with a WiFi scanner is probably going to get you in a lot of trouble.

As such, it's pretty hard to call the stationary assumption unreasonable based on the information given, and it's certainly unreasonable to call it a strawman. Moreover, I hesitate to suggest that anyone who provided advice dismissed his suggestion based on that assumption alone.

Why is the stationary assumption reasonable at all. The OP never mentioned that he was trapped in his basement or did not have access to a laptop. And I'm sorry, but "mathmatically impossible or practically infeasible (the math works, but the numbers are useless)." is frankly BS. There are in fact commercial products which do this on commodity laptops. And I in fact use that software. And it in fact does locate AP's. Honestly barely need the math. Once you get a couple hundred samples and just plot them it's usually obvious where the AP is. And it doesn't really matter how many people in the area are using WiFI because you filter on MAC address.

Actually, he never said he wanted to triangulate using a static access point. That was just a strawman put up by other posters as to why what he was asking for was somehow difficult or even impossible. There are in fact lots of solutions which locate access points, and locating an active client is not really any different.

I am pretty sure that, 'This is similar to using cell towers to "triangulate" a cell phone. I want to locate the device connected to my private wifi,' was not brought up by anyone but ColonelMustard, aka molo's boss.

Quote:

Ummm, all the times I've gone out and taken surveys and the software nails the location of my access points tells me that no, it's not that hard.

Was he asking for locations of APs? Maybe you should go back and re-read the OP since you seem so unfamiliar with it, then come back and tell us what we did wrong.

The commercial products focus on filtering the samples so you only see access points. I've been mentioning AP's because that's what my personal experience is in. I specifically recommended the OP try Kismet instead since I believe it will allow filtering by client MAC instead. Please try to keep up.

Why is the stationary assumption reasonable at all. The OP never mentioned that he was trapped in his basement or did not have access to a laptop

Jesus, dog with a bone? I'll go ahead and quote him for you:

Original Poster wrote:

This is similar to using cell towers to "triangulate" a cell phone. I want to locate the device connected to my private wifi.

Cell towers are stationary. They also have well-known locations.

Quote:

"mathmatically impossible or practically infeasible (the math works, but the numbers are useless)." is frankly BS.

It *is* mathematically impossible to definitively locate a signal of interest with one or two stationary omni antenna. The only way to do so is to *mimic* having more than 2 stationary omnis by moving around and taking discrete samples.

I'm not going to argue this all day. Hopefully the OP will find something useful in my posts, assuming he wades through all the hot air and BS. I think it's pretty clear that everyone arguing that what the OP asked is somehow especially difficult or impossible were mistaken. His goal is misguided perhaps, but essentially lying about how hard it is does not make the forum look good.

but essentially lying about how hard it is does not make the forum look good.

2 measurements versus your 100. Which is harder? What about restricted movement? Nobody here is lying about anything.

Look, I provided a workable approach to solving the problem. And rather than acknowledge that you're taking an overly literal reading of the original problem just so you can keep saying it's really hard or even impossible. I get that maybe you don't want to help the OP. But pretending that what he's asking for is somehow difficult is just plain lying. You know perfectly well it's not that hard. I've seen you post enough to know that you're pretty sharp on networking so I can only presume that your intransigence is intentional and not due to ignorance.

I get that maybe you don't want to help the OP. But pretending that what he's asking for is somehow difficult is just plain lying. You know perfectly well it's not that hard

I'd appreciate if you'd stop accusing me of lying when I've been perfectly rational in explaining myself to you. I *did* want to help the OP, which is why I explained to him how his vision of how it would work, wouldn't. I then went out and found him a tool that would. While it was not as capable as I first surmised (and later admitted in thread), it is still better than trying to use an omni antenna.

The math is the math, and you can call it BS all you like, but it's a cold, hard, physical fact.

Now let's go back to the OP: he mentions he wants to find someone who is on his "private WiFi". From this, I have surmised that he is likely not in a large, open-floor environment such as an office. I can also surmise that the signal of interest is likely within a close enough distance that we're thinking about an apartment complex. In my experience, many apartment complexes are going to severly restrict your movement (which wouldn't happen when heatmapping an open office floor). This means it now becomes more and more troublesome to effecitvely isolate where the signal of interest is coming from.

In this case, a directional antenna will be of much more use than simply heatmapping with many, many spots. Again, it goes back to the math.

Frennzy, TheShark, and LordHunter317 thank you for the educational discussion. It has been truly informational as well as fascinating. I hope it continues. I am ok with hot air as long as it does not contain ad hominem attacks.

HeadlessCow, thank you for defending me. I am glad someone pointed out that I never said “everybody shut up and answer my question.” That never happened; no matter how many times molo continues to claim I did. Also that I very clearly said a few times I did not want to discuss network security measures.

Molo, I never meant to “label” people as sharks and whales. It was a metaphor to separate myself (diatom) into a category of little and insignificant knowledge, and to put the rest of you into the category (sharks and whales) of vast and copious of amounts of knowledge, a metaphor that was quite respectful. Who efs with a Great White Shark? No one. Blue whales are the largest mammals on the planet. Who efs with them? No one, although their temperaments are quite different. Molo, You continue to demonstrate open disdain for me because I asked a question you do not like and also maybe because you know more than me. I am sorry I have disrespected and angered you. I hope in the future you show a little more restraint before labeling others idiots like you did me. (you actually did, and were flagged for it)

SeismoJones, I to believe it is an interesting question and have people like HeadlessCow, ANSDAC and you for encouraging those with the knowledge to continue discussion on an interesting topic. Thank you.

Also when I mentioned triangulation in the OP I meant “similar to triangulation” because it is obvious what triangulation is, I did not mean exactly like triangulation. I wanted to know(still do, and we are closer to it then we were a few days ago) if it is possible to physically locate someone connected to my Wi-Fi.

Also when I mentioned triangulation in the OP I said “similar to triangulation” because it is obvious what triangulation is, I did not mean exactly like triangulation. I wanted to know(still do, and we are closer to it then we were a few days ago) if it is possible to physically locate someone connected to my Wi-Fi.

Yes, you can locate any wireless signal given sufficient resources, time, geography, and energy. It's not really an interesting question in the least, and it's about as specific as anyone can get without more details from yourself.

Moreover, unless you're not being upfront about your intentions, it probably won't solve your real problem, whatever it may be.

I think it's pretty clear that everyone arguing that what the OP asked is somehow especially difficult or impossible were mistaken.

[citation needed]

You cannot say that Frennzy and LordHunter are smart, and then hand-wave them away like that as if it makes your case. You, sir, make the forum look bad.

Whatever. What happened to this forum? A bunch of know it all blowhards seems to be the gist of it. What a waste of my time.

I'm not sure how you judge it to be a waste of time. If your information was correct, it is now preserved for others to enjoy and employ. If not, then it is your own issue for having spent your time on a mistake.

Arguing semantics does tend to be a waste of time but in the case of technical situations it can mean a lot. As poorly as this thread derailed, there is some good info here and if nothing else, it serves as an example of how not to ask for help.

I still think the most elegant and cheapest solution is to just change the password (or turn off wifi) and wait to see who starts bitching.

Of course, the original post isn't completely clear and alludes to some things that will cause mild levels of nerdrage (apparently [although we don't know for sure] using MAC address filtering, etc.). But this phrase, in particular, caused my head to ache:

Quote:

I have done some light research on the topic and come up with very little. The most common response to this question is "Just change your password". Thank you but that does not help me. Any serious person knows it is possible to get around passwords.

It would appear to indicate that the OP feels that password protection is insufficient and that, instead, he wants to actually locate where the person/object is, from:

Quote:

I would like to locate a device connected to my private wifi. To be clear, I am not looking for the IP address of the device, I am looking for the actual physical location of the device that is connected to MY wifi.

However, if a 32-mixed-character password is insufficient to protect one's network, one has a mighty adversary indeed. Although, at base, no security is perfect. You just need to make access less attractive than everyone else's. And change things. Regularly. And, at least as of right now, eternally. Just like locking the door to your home. No, it won't necessarily keep people out; but it's more work than the person down the street that never locks their door.

We have no idea of the area he's talking about: neighborhood, university campus, apartment building, condo, etc. All of which present different scenarios depending on their size and location. A small apartment building near the edge of a small town would be different than a large apartment complex in the middle of a city. Some places may be easier to wander with a laptop and return useful info than others.

For me, I'd have a pretty good idea of whom was using my wifi signal because there are only nine neighbors. The next nearest house is two miles away. So any "triangulation" I needed to do would involve walking a grand total of 1/2 mile and knocking on doors.

So, specifics and details would have made the OP better and might have provided more concrete advice.

Whatever. What happened to this forum? A bunch of know it all blowhards seems to be the gist of it.

You're complaining mightily for someone who is blowing very hard. Frennzy's provided a number of diagrams, you've stated there's software that does something with APs and could probably be modified to use this, then backed it up with repeated recollections of doing site surveys and identifying APs. It is difficult to take your complaint seriously when you're contributing to the problem you complain about.

Just curious (and yes, I'm aware that this is potentially only tangential to the OP) but I wonder if you could get a lot more samples by setting up multiple APs on the same SSID, and then selectively scheduling them on/off to force the client to associate with the one you want. Over time that would be less labor intensive than physically walking around with a laptop or AP, which means you could take a lot more samples.

And, regarding triangulation, even having fewer than the required number of measurements can give you useful information, such as if one of two mathematically possible solutions is in a physically impossible location.

And none of that means locating a device is "easy" by simply using signal strength. Having both strength and *directionality* is always going to be an advantage. An advantage you don't have with traditional omnidirectional antenna.

I'm confused by what you're trying to say here. If you make a measurement of "directionality", you always do so by either measuring amplitude (peak or null), phase angle between multiple antennas, or both. Having both is essentially mandatory.

If you're trying to say that making multiple measurements of different types, like an angle measurement and a time measurement, at the same location is always an advantage, that's not really true. It can be true in specific scenarios, but the two measurements quickly become redundant, as both are measures of position.

It's the same anywhere. Ask an intentionally obfuscated and frustrating question to a specialized audience and you will get a reply asking for clarification. If you then refuse to cooperate, you're not going to get good results.

All the WiSpy gives you is power by frequency. You can't tell anything about what the device actually is. You could try and figure out which of your neighbors had a WiFi device on the same channel as you but that's about it. And really, unless the device is actually sending a lot of data you'll never even notice it in the noise. Thats my experience in using one.

It seems like a massive ooversight not to include a WiFi decoding module if you're going to build that big block of software for spectral analysis.

And, regarding triangulation, even having fewer than the required number of measurements can give you useful information, such as if one of two mathematically possible solutions is in a physically impossible location.

For those sorts of situations to occur, you have to enough measurements for your solution to resolve to a point. The minimum number of measurements to get a point doesn't yield a single point in all geometries. However, if you have fewer measurements than the minimum, you still have line(s) pretty much no matter what.

And, regarding triangulation, even having fewer than the required number of measurements can give you useful information, such as if one of two mathematically possible solutions is in a physically impossible location.

For those sorts of situations to occur, you have to enough measurements for your solution to resolve to a point. The minimum number of measurements to get a point doesn't yield a single point in all geometries. However, if you have fewer measurements than the minimum, you still have line(s) pretty much no matter what.

I thought two radii from two known points in planar space would give you two points, no?

But the general point remains that even imprecise (but correct) location information can be useful. I frequently use Find Friends to locate my wife's phone, and it will occasionally give me a circle of uncertainty that is literally a mile in diameter. But this is enough for me to tell her that she _didn't_ leave it at work, and that it's likely somewhere in the house.

Frennzy wrote:And none of that means locating a device is "easy" by simply using signal strength. Having both strength and *directionality* is always going to be an advantage. An advantage you don't have with traditional omnidirectional antenna.I'm confused by what you're trying to say here. If you make a measurement of "directionality", you always do so by either measuring amplitude (peak or null), phase angle between multiple antennas, or both. Having both is essentially mandatory.

Directionality means using a directional antenna...you can stand in a single point, and rotate. At whichever bearing you get the highest strength of signal, you are most likely facing the signal of interest.

Quite, but you didn't answer my question. You still haven't clarified whether you're trying to say:Direction finding requires making a measure of signal amplitude, which is true for classical beam/null forming systems.-OR-Making two position measurements of different types (e.g., time and direction) from the same location is always beneficial, which is generally not true.

Quite, but you didn't answer my question. You still haven't clarified whether you're trying to say:Direction finding requires making a measure of signal amplitude, which is true for classical beam/null forming systems.-OR-Making two position measurements of different types (e.g., time and direction) from the same location is always beneficial, which is generally not true.

Not sure what I'm not communicating: Statement one above is what I meant.

Statement two is not what I said...but I *did* previously say that you can use two directional measurements (from two different locations) and use the intersection to determine location.